Directive radio system



DIRECTIVE RADIO SYSTEM Fil ed March 13, 1945 4 Sheets-Sheet l SYSTEM Inventors: Richard W. porter,

Anthonl G. Linowiecki,

by AM Their Attorneg.

July 27, 1948. I i R. w. PORT-ER ET AL DIRECTIVE RADIO SYSTEM 4 sheets-sh eet 2 illjvd March v Inventors 3 Richard \N. Porter,

NR BMW C E w o .m L G H n o h .C n A TheiZ Attorney.

July 27, 1948. R. w. PORTER ET AL.

DIRECTIVE RADIO SYSTEM Filed March 13, 1945 4 Sheets-Sheet 3 Fig.5.

0 w QSPW W w m m mw wmt Wan wwwh July 27, 1948. R. w. PORTER ETAL. 2,446,024

DIRECTIVE RADIO SYSTEM Filed March 13, 1943 4 Sheets-Sheet 4 -Fig.6a. Fig. 613. Fig. 6c. VOLTAGE BETWEEN VOLTAGE BETWEEN VOLTAGE BETWEEN CONDUCTORS l/4-l/4 CUA/QUCTORS 35 CONDUCTORS 34 TARGET BELOW AXIS OF ROTATION Fig. 7a. Fig. 7c.

,v Fig. 7b.

TARGET RIGHT OF AXIS 0F ROTATION Fig. 8a. Figfib. 139580. I

I M me TARGET ABOVE AXIS 0F ROTATION TARGET LEFT OF AXIS F ROTATION invemtowsi Edward W1 porter, Anti-10mg fiuLinowi'eck b fi mw Thai? Afitlcr' nei m Patented July 27, 1948 DEREC I SYSTEM Richard W. Eorter, Schenectady, N. Y., and

Anthony G. Linowiecki, Minneapolis, Minn, assignors to General Electric Company, a corporation of New York Application March 13, 19%3, Serial No. M8394 invention relates to directive radio systems and more particularly to certain improvements with respect to the control of the orientation thereof. 1

;In"copending application Serial No. 414,126 of I QSi'dn ey Godet filed October 8, 1941, and entitled D rective radio systemi W Patent No. 2,412,612 issued, December- 17,.1946,-which application is I assigned tqthesame-assignee as our present appli- ,cation,;.isdiscloseda directive radio system havfig m an whereby it ismaintained oriented in the-direction; onpropagation of received waves. a Thus; if the-system be carriedby an aircraft and isdirected at a remotecraft from which it receives 1 radio waves,-1as .by reflection of waves radiated from the system, or byreception of waves radiatedfrom the-remote craft, the system is auto matically maintained directed at the remote craft irrespective on-the relative -movernents of the f qtwo fil'afts. I. J 1 I. object ,of: our; present invention is to pro- ,;vide;such.a. system with means' for scanning a rcmoteareaiin, the absencezof received waves together with means responsiveto waves received from the. area scannedtointerrupt the scanning operation =while the system isdirected in a direction sufliciently near the object from which the I received waves arrive :to ;enable the orientation ,ofthesystem to ,be controlled by the direction of the receivedwwaves :ratherthanby'the scanning ,means. a The -scanning. ;,means mawthen be disabledand thesorientatiom iollowsithe remote objectautomaticallm; '1.

, A furtherobject, provide means such that the received wavestakemontrol .of; the orientat Qn fihqsysteijndespitetheaoperation of the ...--scanning; controlmeam;

Another;phjectvof our; nvention to provide guiprnentgsp that the operator may ns; means:

' ,ention: is to provide at a minimum of his to provide u v eto be char- Whi e 611 .on are .set forth with parlga at er t th further obeer-e9 gra @sibeunderga er ei stgohilefifiivedgwaves take con-.

13 this. (on. 343-7) ing in which Figs. 1, 2 and 3, when taken together represent an embodiment of our invention, and Figs. 4, 5, 6, 7, 8 and 9 represent certain characteristics of its operation.

Referring to Fig. 1 of the drawing we have shown in the upper portion thereof, in a very conventional way, a radio system which may comprise an antenna arranged within. as at the focal plane of, a reflector I. This reflector I may comprise any conducting surface, preferably in the form of a surface of revolution. Commonly such reflectors are of paraboloidal form having an antenna at the focal point thereof. This antenna, together with the reflector I, may be considered to have a directivity pattern about an axis 2, this axis being the axis of directivityof the system. The reflector I may suitably be mounted on a shaft 3 arranged for rotation in a bearing 3, and such other bearings as may be required when driven by a motor 5 arranged on the shaft. The axis 5 of the shaft 3 extends at an angle of a few degrees to the axis of directivity 2 of the antenna system and accordingly the axis of directivity 2 is rotated about the axis 6 of the shaft 3, its path of revolution comprising the surface of a cone. Waves received from the direction of the axis 6 are therefore received with uniform intensity in all positions of the antenna system i in its rotation, except for such variations in intensity as may be produced by causes, such as, for example, changes in the plane of polarization of the antenna. Waves received from any direction other than the direction of axis 6, however, affect the receiving antenna diiferently by reason of its different orientation when the system is at different points in its path, and the result is a periodically varying responseof the antenna to such waves. This periodically varying response has a time phase relation dependent upon the direction from which the waves are received with respect to the direction of orientation 6 and this time phase relation is utilized to control the orientation of the system, that is, to control the direction of the axis 5 to maintain that axis directed along the line of propagation of the received waves.

This cyclical variation in response of the system to waves received from directions other than the direction of axis 6 may be produced either by rotating the reflector, the antenna, or both as desired. In systems where the reflector is too large it is preferable to rotate only the antenna. To vary the orientation the center of symmetry of the antenna may be moved about the focus of the reflector without rotating the antenna itself. For reasons of mechanical simplicity of the an- 3 tenna, however, the antenna itself may also be rotated about its point of symmetry.

The shaft 3 is arranged for rotation about the horizontal and the vertical axes. The bearing 4 is mounted for rotation about the axis of horizontal shaft 1. This shaft is mounted for rotation in bearings 8 and is provided with a gear sector 9,

which cooperates with the gear i driven by a motor I l whereby upon operation of the motor I l the shaft I may be rotated in a vertical plane about the horizontalaxis 1 thereby to project the axis of orientation 6 at any desired angle in the vertical plane. The bearings O. sup'porting'the horizontal shaft I, may be supported upon a horizontal ring gear II, which cooperates with the gear II driven by a motor l4 whereby upon operation of the motor the ring gear I! is rotated in the horizontal plane thereby carrying the shaft 4 which in turn controls Similarly the voltage between conductors II is supplied through contacts of relay 36 across condensers 48 connected between the control electrodes of discharge devices 41 and 48 which in turn control generator 49, the voltage of which is supplied to the motor l4 over conductors I0.

This portion of the system operates to maintain the antenna directed at any remote source of received waves. The electron discharge devices 38, 40, "and 48 are also controlled by equipment shown in Fig. 3 to effect scanning of a remote area. This equipment comprises a plu-v rality of relays 54, 55, 58 and 51, which are connected through conductors 58, 5!, i0 and ii to certain contacts 64, N, 86 and Cl associated with the rotating shafts of the system of Fig.1. These relays operate to control a plurality of discharge devices 00, 09, I0 and Ii, which in turn control the'screen' grid potentials of discharge devices 41,

' 40,10 and 40 of Fig. 2 over conductors I4,

represented by a dotted line I. on the drawin and extends through the vertical shaft l8 and through the horizontal shaft I, thence through an interconnecting member i9 to the horizontal shaft 3 through which it passes to the antenna of the system I. -These various shafts are hollow to include the transmission line ID. This line may comprise a central conductor, which may be considered as represented by the dotted line It, and an outer conductor which is grounded. Rotatable joints 2|] are provided at the left end of the shaft 3, at the left end of the shaft I, and at the-bottom of the shaft" to permit rotation of these respective shafts about their own axes.

Radio frequency potentials induced in the antenna are supplied through the transmission line II to radio equipment II where it is amplified, converted in frequency as desired. detected, and the resulting pulses of unidirectional current are supplied over conductors II to equipment indicated in Fig. 2. They are also sup lied through conductors represented by cable 22 to equipment 23 where they are utilized to control various cathode ray indicators three of which are indicated respectively at I, I" and I'. The character of indication produced by these indicators is indicated in Fig. 1 and is described later herein.

The equipment of Fig. 2 comprises a plurality of electron discharge devices 24, 25, 26, 21, 28, 29 and 30. The devices 21, II, 29 and" are arranged to produce two unidirectional voltages, I one between conductors 34 and the other between ductors I4 is supplied through contacts of relay TI to condensers 8. connected between the control electrodes of discharge devices a and 40.

' The anode currents in these discharge devices control the voltage produced by generator 44 It and 11. This operation is such that inthe absence of any received signal the system of Fig. l

scans a remote area of space; thatis, with the system described the direction of orientation of the system I is varied about the periphery of a rectangle in remote spacein the absence of any received signal. If a signal be received during such scanning operation, it takes controlof the discharge devices 39, 40, 41 and and interrupts the scanning operation in a manner later to be described. The operator may then open switch ill of Fig. 3 and thereby disable the scanning mechanism whereupon the system of Fig. 1 is maintained oriented in the direction of the received signal.

In the lower left hand corner of Fig. 2 is shown a handle 83 mounted upon a shaft 84 about which it may be rotated, and which may also be rotated about a shaft 85, together with means comprising discharge devices 86, 81, 88 and 89 which may also control the grids of discharge devices 39, 4D, 41 and 48 to vary the orientation of the systemofFig. 1 in accord with the movements of the handle 83.

As previously indicated, waves received from the direction of the axis 6 are received with uniform intensity in all positions of the antenna. Waves received from any other direction, however, are received with greater intensity when the axis of directivity 2 is in closer agreement with the direction of propagation of received waves and with less intensity when it is least in agreement with said direction of propagation with the result that the signal supplied from the apparatus ll over conductors 2i varies cyclically. Commonly wth equipment of the type described the received signal is an echo of pulses radiated by the system I, these pulses being produced by the transmitter l1 and supplied to the antenna of system I for radiation thereby. Such pulses may impinge upon any remote reflecting surface, such as an aircraft, and be received on the, antenna and transmitted to the equipment I! where they are amplified, converted in frequency, translated to unidirectional pulses and then supplied over conductors 2| to the detector of Fig. 2. These pulses may have thecyclically' varying character shown in Fig. 4. They are demodulated by detector 24 and produce upon resistance 90 a cyclically varying unidirectional potential such as that indicated in Fig. 5. This potential is supplied through condenser 94 to resistance 85. A portion of this potential is supplied to the motor ii overconductors indicated by the arrow through Selsyn input of amplifier 26 where it is amplified and supplied through a frequency responsive coupling device 96, commonly a transformer as shown at 96, to the control electrodes of a pairof electron discharge devices in the envelope 20. These discharge devices are connected in balanced, or push pull, relation the cathodes being connected to ground through resistance I and the control electrodes being connected to the opposite terminals of the secondary winding of transformer 96. The anodes are connected together through resistances I00 and I05, the

point between these resistances being connected produce potential variations of opposite phase upon the two anodes of the discharge devices in envelope 26. .The potential on the anode II 0 of the discharge device 26 is supplied through condenser H3 and conductor II a to the upper control electrode 5 of the discharge device in envelope 21 and to the control electrodes I I6 in the lower discharge device .in envelope 2B. The potential on the anode I I! of amplifier 26 is supplied through condenser I I0 to the control electrode III! of the lower discharge device in envelope 21 and to the upper control electrode I20 in envelope 28. These potentials are also supplied to corresponding control electrodes of the discharge devices in the envelopes 29 and 30.

The anodes of the upper discharge device in envelopes 27 and 28 are energized in phase but in opposite phase relation with the anodes of the lower discharge devices in these envelopes, these upper anodes being connected to one terminal of the secondary winding of transformer IZIiand the lower anodes being connected to the lower terminal of this secondary winding. The anodes of the discharge devices in envelopes 29 and 30 are similarly connected with respect to the secondary winding of transformer I25. The primary windings of these transformers I24 and I25 are energized from a three-phase generator I26 mounted upon the rotating shaft 3 of the scanning equipment. Since this shaft rotates at the rate of rotation of the axis of directivity 2 about the axis of orientation 6, the frequency of the voltage supplied by the generator I25 is the same as the frequency of the cyclical variation in the received signal. o I

Any suitable means may be provided to vary the phase of the output from generator I26 with respect to the phase of the rotation of the axis of directivity for initial alignment and to compensate for phase shifts in the electrical circuits and amplifiers. Such means is indicated in Fig. 1 by the arrow through generator I26 and may comprise means for mechanically rotating the stator of generator I26 about shaft 3 or it may comprise suitable phase shift means in the electrical circuit of this generator. Similar means is generators 203 and 204 later referred to.

The voltage of generator I26 is supplied over the three conductors I27 to the primary windings of the transformers I2e,,I25. These transformers are .connected in the ordinary, so-called,

Scott fashion, the primary of transformer I24 being connected across one phase of the threephase circuit and the primary winding of the transformer I25 being connected between the third phase of the three-phase circuit and a midtap on the primary winding of transformer I26. Thus the voltages across the secondary windings of transformers I24 and I25 are in quadrature phase relation.

If desired, of course, generator I26 may itself be a two-phase generator thus eliminating transformers I26 and I25.

The midtaps of these secondary windings are connected to a point of positive unidirectional potential between resistances I08 and I09. The potential on resistance I09 is less than the amplitude of alternating potential on the secondaries of transformers I26and I25 so that each anode is driven negative with respect to its respective cathode during the negative half cycle of the anode operating potential.

The cathodes of the discharge devices in envelope 21 are connected together and to ground through resistance I20, and, similarly, the cathodes of the discharge devices in envelope 28 are connected together and to ground through resistance I26. The cathodes of the discharge devices in envelopes 29 and 30 are likewise connected to ground through corresponding resistances I30 and I33. resistances I28 and I29 are connected through conductors 34 and contacts I34 and I35 of relay 31 in its lower position and resistances I36 and I3! to the control electrodes of discharge devices 39 and 40. Between these electrodes are connected the capacitors 38 each of which is connected between therespective control electrode and ground. Similarly the opposite terminals of resistances I30 and I33 are connected through conductors 35. contacts I38 and I39 of relay 36 in its upper position, resistances I40 and IM to the control electrodes of discharge devices Q1 and 48. Between these control electrodes are connected the condensers 46, each being connected between its respective control electrode and ground. The cathodes of these devices 41 and 48 are connected through a variable resistance Hi5 and the contacts I46 of a relay I 67 to ground. Similarly the cathodes of devices 39 and 40 are connected through variable resistance I46 and contacts I40 on relay I50 to ground. The

anodes of the devices Ill and 66 are connected through respective field windings I5I and I52 of the amplidyne generator 49 and through conductor I06 to the source of potential I01. Similarly the anodes of devices 39 and 00 are connected through the respective windings I50. and IE5 of amplidyne generator 04 and thence through conductor I06 to the source of operating potential. The relation between the currents in these two windings of each generator determines the magnitude and polarity of the voltage developed by the respective generator, which voltages are supplied over circuits 45 and 50 to the respective motor's II and I I, which vary the orientation of the antenna system in elevation and azimuth, respectively, the direction of operation of these motors, of course, being dependent upon the polarity of the voltage supplied thereto.

The operation of the system as thus described may best be understood by reference to Figs. 6, 7, 8 and 9. As previously mentioned, a voltage such as that represented in Fig. 5 appears upon the resistance 90. The sawtooth,v or serrated, character of this voltage is reduced by the tuned The opposite terminals of transformer 96 or alternatively by any other suitable low frequency coupling device and a subthat supplied to the control electrodes in de-- vice 30. I

Let us assume, for example, that at a particular instant the axis of directivity 2 is directed at a remote source or radiation, or at a remote reflecting surface from which pulses radiated by the antenna I are received. Let us also assume that this remote source'of radiation is directly below the axis of rotation 6 and that the cyclically varying voltage between the conductors I16 and H6 is as shown in Fig. 6a. The voltage from generator I26 may be so phased that this cyclically varying signal voltage either agrees in phase, or is in opposed phase relation with the voltage upon the anode of any of the discharge devices in envelopes 21 and 26. That is, the control electrode H6, for example, may be positive during the positive half cycle -of its anode operating voltage and the control electrode IIS may be negative during the negative half cycle of the operating voltage applied to its associated anode, and similarly the control electrode I20 may be negative when its associated anode is positive and the control electrode II6 may be positive when its associated anode is negative. Since all of these control electrodes are biased positively with respect to their cathodes fromresistance I 69 through conductor I63 and resistances I66 and I66, a substantial anode current flows in each device when its anode is positive. The magnitude of this anode current is substantially unaffected by the anode voltage because of the magnitude of the cathode circuit resistors I26 and I26, which may be of the order of 100,000 ohms, but is controlled by the voltage impressed upon the control electrode. Thus since the control electrode I I6 is positive when its associated anode is positive, an increase of current occurs in this device and in resistance I26. At the same time control electrode I26 is negative while the anode is positive thereby reducing the currentfiowing in this device and in resistance I26. Thus a voltage appears between conductors 36 during this particular half cycle of the received signal, which voltage may be considered as represented by the intermediate half cycle of the voltage wave I66 shown in Fig. 6c.

Of course, during this half cycle the anodes of the lower devices in these envelopes 21 and 26 are negative with respect to their cathodes and thus these control electrodes H6 and I I6 have no effect. During the next half cycle, however, these lower anodes are positive and the control electrode 9 is positive while control electrode I I 6 is negative. This means again an increase in I 8 ed'by the distance between the axis I61 and the dotted line, I68 in Fig. Be. This cyclically varying wave I66 is supplied through resistances I36 and I3! to the condensers 36 where it produces an average unidirectional charge having the magnitude and polarity indicated by the dotted line I66 of Fig. 6c. The alternating component is substantially eliminated by thefiltering effect of these condensers and resistances I36 and I61.

Let us assume that the polarity'of this voltage on condensers 36 is such that the control electrode of device 36 varies in the positivedirection and the control electrode of device 66 varies in the negative direction. Increased current then flows in the winding I66 of generator 66 and decreased current in the winding I66 of this generator. This causes a voltage to be developed by the generator between conductor 66 tending to wardly toward the source of the received waves.

orientation 6.

Since the anodes of the discharge devices 36 and 30 are energized inquadrature with respect to the anodes in devices 21 and 36. the voltage which appears between the conductors 36 has the form indicated in Fig. 6b. This voltage is symmetrical with respect to the zero axis I61. Thus no charge is developed on the condensers 66 and the generator 66 develops no voltage and the motor I6 is, therefore, not operated.

Now let us assume that the target of the radiated pulses is directly to the right of the axis of The maximum of the received waves now occurs one quarter cycle later than before, as indicated by Fig. 7a, so that the voltage on the control electrode of the upper device in envelope 26 is positive when its anode is positive and the voltage on the lower controlelectrode of this device is negative when the anode is negative.. Thus the voltage between conductors 36 is of the form indicated in Fig. 7b and that between conductors 36 is or the form indicated in Fig. 7c. A unidirectional voltage is now developed on condensers 66 thereby causing generator 66 to produce a voltage which is supplied to the motor I6 to vary the orientation of the system in azimuth to orient the axis 6 toward the target. I

Since the wave of Fig. 7c is symmetrical with respect to the zero axis I61, no charge is developed on condenser 36 and the motor II is not operated.

If the target be above the axis of rotation 6, then the situation represented by Figs. 8a, 8b and 8c is present. A unidirectional voltage indicated by the dotted line I66 of Fig. 8c exists on condensers 36 but is of opposite polarity from that which previously existed on these condensers as represented by the line I66 of Fig. Be. This causes the operation of motor II to raise the orientation current in resistance I26 and a decrease in curdirectional component of the magnitude indicat- -of axis 6.

If the target he at the left of the axis of rotation, then the situation is represented by the curves of Figs. 9a, 9b and where unidirectional voltage is indicated on condenser 66 opposite in polarity to that indicated in Fig. lb, and motor I6 is operated to vary the orientation6 toward the target.

It will, of course,be understood that if the target be in any other direction with respect to the axis 6, both motors may be operated simultaneously to direct the axis 6 at the target and that this operation goes on continuously thereby maintaining the axis 6 directed at the target. 0! course, when the axis 6 is directed directly at the target, the cyclical variation in the received signal disappears and the motors H and it become deenergized, but as soon as there is any appreciable variation between the direction of the target and the direction of axis 6 this cyclical voltage variation exists and the motors respond to orient the axis 6 at the target.

In the operation of apparatus such as described, hunting is likely to occur; that is, either generator 44 or 49 produces a voltage to correct any deviation between the orientation of axis 6 and the direction of the target and this voltage continues until this deviation is corrected. It is not corrected, however, until the axis 6 is directed at the target within a very narrow range of accuracy with the result that because of the inertia of the rotating parts, etc., the axis 6 may be driven beyond the target. If this occurs. the phase of the cyclical variation in the received signal reverses, causing the voltage of generators at and 49 to reverse and the opposite correction to be brought about, but again the axis may be driven beyond the target, this cycle of operations repeating and setting up the usual hunting phenomenon.

To avoid this efiect, the voltage of generator 49 is supplied through conductors ill! across a series of three resistances NE, N2 and H3. These resistances are shunted by a potentiometer lid the upper terminal of which is connected through a condenser I to the control electrodes of discharge devices 68, and a variable contact 18! on potentiometer l'l l is connected through condenser I16 to thecontrol electrodes of discharge devices 69. The cathodes of these devices are connected together through a resistance ill having a variable tap which is connected to ground through a resistance H8. The anodes of devices 68 and 69 are connected together through resistances H9 and I89, the point between these resistances being connected to the source of operating'potential. The anodes of device 58 are also connected through conductor iii to the screen grid of the discharge device 6'1, and the anodes of devices 69 are connected through conductors 75 to the screen grid of device 38.

In this way, whenever a charge is developed on condensers at in response to a received signal, generator 49 produces a voltage of a certain polarity to bring about the correction in orientation. That voltage is supplied through the discharge devices 68 and 69 to produce a voltage on the screen grids of devices 4? and 8, tending to counteract the initial effect of the charge on condensers 46 thereby to reduce the voltage produced by the generator 39. This reduces the tendency of the system to overshoot and avoids any hunting efiect.

Of course, the generator A l is also connected through conductors I83 and a network similar to that previously described to the input of discharge devices 10 and H, which in turn control the screen grid potentials in discharge devices 39 and 4B.

In the operation of the equipment as thus described it is necessary first to orient the system in the neighborhood of the remote target or source of radiation, such as a reflecting surface. Since the target may be invisible, however, either because of distance or atmospheric conditions, it is desirable that theremote space be scanned for the presence of any target that may exist therein. For this reason the system comprising relays 54, 55, 56, 51, I83 and I85 is provided. This relay system-is connected through conductors 58. 59, 60 and Bi to switches 66, 65,

i 66 and 61 which are operated by cams I86, lal, I88 and H89, the first two of which are mounted upon the shaft l for rotation therewith and the latter two of which are mounted for rotation with shaft it. These cams and this relay system are arranged to cause the equipment of Fig. 1 to scan a rectangle in remote space. When such scanning operation is desired, the operator closes the switch 80 shown in the lower portion of Fig. 3. This energizes relays I36, 435 and be from a source of potential 190 through obvious circuits including conductor 895 and switch til. The source I90 may be of 23 volts and is shunted by equal resistances I93 and E98, as shown in Fig. 3. Thus conductor I95 is 24 volts positive with respect to ground and conductor 59%, con-= nected between resistors-193 and Nd, is 12 volts positive with respect to ground. Prior to energization of relay I84, lad, this 12 volt conductor W6 is connected to all of the control electrodes of devices 68, 69, i0 and lit. It is connected through the lower armature of relay i8 1 in its lower position to the control electrodes of discharge devices 68 and 69, and it is connected through the upperarmature of relay 0%, in its lower position, to the control electrodes of discharge devices iii and ii. Thus these control electrodes are normally all biased 12 volts above ground. Of course, because of current flowing in resistances Hi3 and 2%, these control electrodes may be negative with respect to their associated cathodes. This condition with respect to devices ta and 69 still exists after relay 584i operates since its lower armature maintains the control electrodes of device 6% connected-to the 12 volt terminal use and its two upper arma tures connect the control electrodes of device $9 to this 12 volt terminal through a path including the upper armature of relay 68d, resistances iii and H2, middle armature of relay ltd, lower armature of relay 5? in its lower position, and lower armature of relay 5% in its lower position. Thus discharge devices 68 and 6% remain in active.

Relay 585 by its upper armature maintains the control electrodes of device it connected to the 12 volt conductor ice. It, however, connects the control electrodes of device it to the 2% volt terminal 595 through a circuit extending from the control electrode of device it through the lower armature of relay ltd, resistances H3 and H2, middle armature of relay B85, lower armature of relay 5G in its upper position to 24 volt conductor H95. Thus current passed by the anodes of discharge device it is greater than that passed by the discharge device it thereby driving the. screen grid of discharge device d8 less positive than the screen grid of discharge device 39. This causes an unbalance of current in field windings we and i575 and a voltage is developed by generator dd between conductors d5 of such polarity as to cause motor it to rotate in a direction to elevate the orientation of the antenna system.

This voltage developed by generator id is also supplied back through conductors I83 to resistances ill, I72, I13, which are shunted by potentiometer resistance I'M. A suitable portion of it, determined by the position of variable contact [81' on resistance lid, is supplied between the control electrodes of devices 10 and H with polarity opposing the initial voltage of 12 volts between these control electrodes. This reduces the voltage diiierence between these control electrodes, and between the screen grids of derelatively small potential between control elec-' trodes of devices II and II causes iull running excitation of generator 44. Therefore, the voltage developed by this generator during this running condition and hence the speed at which motor M is driven is determined by the position of contact Ill and may be varied by variation of that contact.

In this way, the voltage supplied initially to motor II -is sufliciently greater than the voltage supplied during the normal rimning condition to produce rapid starting of the motor. This voltage is then automatically and rapidly reduced to a stable running, or equilibrium, value which continues during the remaining operation of the motor.

This operation not only has the advantage of producing rapid starting of the motor but also renders the speed at which it operates independent of variations in the characteristics of discharge devices Il, II, it and ll and independent of variations in the anode operating voltage supplied to these devices. I

The operation of motor ll continues to clevate the antenna until cam lll engages the armature oi switch 85 closing this switch. Conductor I! is then grounded through switch" causing energization of relay II through the upper armature oi, relay 5'. Relay ll operates and by.

The lower armature of relay ll, however, in its upper position connects the control electrodes of device it to the 24 volt conductor through a circuit which extends from the control electrodes of device ll through the upper armature 0! relay lll in its upper position, resistances I'll and I'll, middle armature of relay Ill in its upper position, lower armature of relay II in its lower position, and lower armature oi relay II in its pper position to the 24 volt conductor I". Thus device It now passes more current than does device ll, thus lowering the voltage on the screen grid oi device 41 to a value lower than that on the screen grid of device 40. This in l2 mature oi relay It in its upper position now connects the control electrodes of device II to ground through a Path as follows; control electrodes of device I I, lower armature of relay Ill, resistances Ill and "2', middle armature of relay Ill, lower armature oi relay is in its lower position and lower armature oi relay It in its upper position to ground. This means that discharge device II passes less current than discharge device ll thereby increasing the screen grid voltage of discharge device 40 to a value greater than the voltage of device 3!. This causes generator 44 to produce a voltage opposite in polarity to that last produced, driving the shaft I in a'direction to lower the orientation of theantenna.

This operation. continues until cam ll! causes a the closing of switch '4 and the grounding oi thereby increasing the screen grid potential on device" with respect to that on device 48 and causing generator it to produce a-potential of opposite polarity to that previously mentioned, thus driving the scanning system in a counterclockwise direction moving the axis 6 to the left. This operation continues until cam I" causes closing of the contact 68 when relay 84 again becomes energized.

This cycle oi operations repeats indeflni thereby causing the axis. first to be moved upwardly, then to the right, then downwardly, thence to the left and thence again upwardly,

continuously thereby scanning a rectangle in remote space. The dimensions or this rectangle may be varied by variations of cams ill, I", III, I" about their respective shafts. The rate at this scanning operation is controlled by the position of the variable contacts Ill and III.

This operation is effected-through the same discharge devices '0, ll, II and II throughwhich the anti-hunting operation is secured and the devices it, 40, 41 and ll operate both in response to the scanning voltages controlled b the turn causes'generator 0 to supply voltage to as motor ll oi such polarity as to operate the scan-- ning device in the clockwise direction thereby movingtheaxislto theright.

01 course, the voltage oi generator 4! is likeously or until such time as waves are received wise supplied back to potentiometer Ill and go then between the control electrodes of devices II and ll, with polarity opposite the initial actuating voltage and to reduce this input voltage to the stable running value exactly as was described in connection with the operation of mo- 08,

energised through the upper armature oi relay 10 ll. Relay It operates and deenergizes relay It. Relay 88 returns to its normal position and thus restores the connection or the upper control electrodes oi device I to the 12 volt conductor I received in the receiving system. Voltages arev then developed upon the condensers II and u in accord with the direction of the remote aircraft, andthese voltages may be or sumcient magnitude to take control or the discharge devices ll, ll, 41 and II to cause the system to be oriented in the direction of the remote aircraft.

I! the received signal is suiiiciently strong such orientation occurs, as previously described. However, as axis t approaches the direction of the remote aircraft, the cyclic variation in the received signal decreases and thecharges on condensers SI and II tend to disappear. The potentials supplied to the screen grids or dethereby dcenergizing motor I. The lower ar- 1| vices 41, 48; or II, 4|, from the scanning mech- By. its middle ar-- anism of Fig. 3, on the other hand, remain. Therefore the axis 6 does not become oriented directly toward the remote aircraft, but rather to one side. above, or below, depending on which of relays 56, 55, 56 and 5'! is energized. The amount of the misalignment is such that the voltage across condensers 38 and 56 just balances the effect of the screen grid voltage applied by the devices til. 48 or 39, db in the anode circuit of these devices.

If the intensity of the received echo be insufilcient to balance the effect of the scanning voltages on the screen grids of devices 3?, til, 39, ill, in the anode circuits of these devices then the scanning operation continues but is afiected in the following way by the received echo as the axis E passes in the neighborhood of the target: As the axis of orientation 6 approaches the target the voltage variation on condenser 38, 8E aids the voltage supplied to the screen grids of devices 5?, S3; 39, w from the scanning system in producing voltage from generators 3 and $9 to orient the axis t3 toward the target. As axis 6 crosses the target the voltage due to the echo disappears and that from the scanning system tends to cause the system to resume its scanning operation. As the axis d leaves the target the voltage due to the echo reappears but opposes the scannin voltage and retards the motion of aids it away from the target. Thus the equipment tends to hasten its orientation toward the target and to hesitate in leaving the target.

The operator may, after observing either of these last two types of operations, open switch 88, thus deenergizing relays laid and H85 and that one of relays 56 to El that may be energized and disabling the scanning system, whereupon the system accurately follows the remote target.

The indicators represented at I, I" and Fig. I produce indications of these operations of the system and also indicate the direction and range of the remote target. These indications may be produced by cathode ray oscillographs on the viewing screens of which are produced indications, of which those shown in Fig. l are representative' The cathode ray oscillograph I" has its cathode ray deflected, by means not shown, about a circle as shown at 236 as the axis 2 is rotated about the ans t. This ray is also deflected about a rectangular path 238 on the fluorescent screen as the axis d is scanned about the rectangle in remote space. The deflection voltages necessary to this control may be developed by the Selsyn devices 292 and 2% or by any other suitable means. During the scanning the luminescent circle 238 may be seen to move about the path 22% leaving a luminescent path behind it by reason or the persistence of the luminescence of the viewing screen. This persistence and the rate of scanning may be such that the entire path is to some extent luminescent.

If a target enters the remote rectangular area scanned, the luminescense of the circle 2353 iii-- creases, first, because of the tendency of the system to hasten its orientation to the position corresponding to the position of the target and then to hesitate in that position, as previously described, andsecondly, the ray may be rendered more intense in response to the echo from the remote target, as by controlling the grid of the cathode ray device in response to the received echo pulses.

If the remote target be near or of such charactor as to produce a strong echo such that the 2' l "5" mi charges on condensers tit-and fifilhavegreatcr effeet in the anodeuc ircuits .oi-dey-ices '39-, Menu ill, 38, than do. the. voltages supplied to the screen grids of these devices,,.the syste m,then'fol lows the 5 remote target as previously describedeand the circle 2.3g leaves, the path ,23 l. andfollows-a ,path corresponding to the. course oi the target.

The presence one target in the remote area scanned'may be somewhat more readily-observed l0 from'the screen of lthe cathode-ray device I'.

Thecathode ray of this device is .deflectedhorizont'ally ln accord withf variations of theorienta tioii in azimuth. It is deflected, vertically tor a distance corresponding to the range-of theequip- 5 ment and at a frequency high relativetothescam ning movements in'a zimuth. The control electrode of this t'ievieq's coritroll ed by th received echo thereby 'tojproduce an illuminated spot at, a point on the screen.correspondingto the direc- 20 tlon of the remote target ,infazin uth and corresponding to the li ange'o'ffthere rnote target, $uch a spot is indicated at'232'atj, distance from line 2323 c'orresponding'to the raids. Becauseof the persistence ot lurninescen "of. 'the fluorescent screen and the high, ire of the vertical defiection as compared {with the, horizontal do. flection. this s agappgrs in a. luminescent column re'pr'esentedfbyth shaded area t tll having the width of'the spot W and occurring, at a position correspohding'to the direction cathetergetiniazimuth.

The presence of the remote target and its range may also; be 'li'jbslfl: from indicaterllf which may be'operated as .crdi'nary'cathcde ray rangeindicatorjie. tl'i' ray infthis device is deflected horizontally acro's e screen'in. a pre' determined interval start 1th" each radiated pulse; and. it is deflected yqama iy by ther'adiate'd pulse andany echoes redeive d during the interval.

4.) In the drawingtwiidefiectionsafre shown, that in dicated'at 2285 representing the oil going pulse and that indicated. M236 representing an echo 'the're of. 'FIh'ese'defiectiOnS are spaced apart in accord with therangeto theremot eftarget. l, I

When the operator' observes a target inthe area scannedhe opensswitclft d a' dis'a blje the scan ning system: "He then maa 'any I orients the equipment at the target an'd 'theni leaves it to fol low the targetautomatically; 'l hisprocedtu'e is usually preferredover thatof allowing the system to follow thetarget'directlybecause it may follow an undesired target ci orient tse'lf at'a source of echo chime-ground;

Themanner-orientation of the equipment tb,. ward a desired target may be effected'byinanipulation: of-the handie llti shorter in Fig handle iisprovided-with aswitch contro rn by.energizingireldys 'iiiiand377; :Operati o 00 these relaysndis'connects the discharge d sass andidd froih 'conductors 34! asses d sh; nectswthe; control'xelectrodes' of "these discli'aff devicesto the respective cathodes ofdischarge flood-585 t?ddi 'and 8%," respectively; -"l3h vicesi-are;corinected-to -control' devic'es" ll-,- 18," 9 anddBat-o orient the system in accord with the to sitiQDzQfi :mamlal kibntrolamember 83 about-either of, iLWOgitXSS iiiand. 85;. the: first corresponding to elevation; and the :Elatter corresponding to azimuli i -1 cathodes ofwthese latten discharge dea -ices- 86 L 39 gareieach connected'to;ground through a su table fiai'r :zflf -.-.resistances .215,v are, -21 i 2 l as; Th anodesare arran edito'be-energized in phase 1 75 from a suitable source of alternating current 2 l9.

esse'd closescontacts mil 15 This source of alternating current also supplies voltage Over conductor 22. to the rotors of the two Selsyn transformer devices 203 and 204 the stators of which are connected through conductors 224 and 222 to the stators of Selsyn devices 226 and 22!.

It will be observed that the stator of elevation transformer 22 is connected through the conductors 224 to the stator of the Belsyn transformer 203 the rotor of which is mounted upon the shaft 1 and which rotor, therefore, is positionable in accord with the position of the axis 6 in elevation. This position determines the relative magnitudes of the voltages between the different conductors 224. The voltage induced in the rotor winding of Selsyn transformer device 226 is zero when the handle 83 agrees in position with the orientation of axis in elevation. Movement of this handle in either direction from this osition causes voltage to be induced in the rotor of one phase. or the opposite phase, corresponding to the direction of the movement of the handie and of magnitude corresponding to the extent of the movement. This voltage is supplied to the primary of a transformer 240. This transformer has two secondaries 2H and 242 the voltage of each of which is supplied between the control electrode and cathode of the devices I! and 89, respectively, in opposite phase relation; This voltage is of the same frequency as the voltage supplied to the anodes of the devices 88 and I, and if it be in phase with the anode voltage in one device it is in phase opposite the anode voltage of the other device. Thus the anode current in one of these devices is decreased while that in the other device is increased, In this way the magnitude and polarity of the voltage between the cathodes of the two devices 86 and 21 may be varied as desired by rotation of the arm I: about the shaft 84, this unidirectional voltage being supplied to the control electrodes of the devices 30 and II to eiiect the desired control of the motor H to var the orientation of axis 8 in elevation to the position corresponding to the position of handle 82 about shaft l4. Rotation of the rotor of Selsyn transformer 2'3 varies the relative magnitudes of the voltages between conductors 224 and hence that across the primary of transformed 2" until the cathodes of devices I. and 89 are at equal unidirectional potential with respect to ground. When this occurs, motor ll becomes deenergized and stops. In this way the orientation of axis U may be varied to any position in elevation by simple rotation of handl I! about axis 84.

The Selsyn transformer device 22! is connected in exactly the same way with respect to the discharge devices 86 and I1, and 41 and 48, and it is connected through conductors 222 to the azimuth transformer 2 the rotor of which rotates with shaft l8. Selsvn transformer 226, carrying handle 03, may be mounted in bearings in a bracket 23,which may be rotatable about, or geared with, axis I5, thereby to rotate that shaft in accord with the desired orientation of axis 6 in azimuth. Thus if the arm '3, together with the bearing bracket 2!! and Selsyn device 220. be rotated as a unit about the shaft I. a corresponding control of the device devices I. l1, l1, and II and azimuth motor ll may be efl'ected to vary the orientation of axis t to the direction oi the target. When the target appears upon the screen of the cathode ray devices I, I". 1". or on that one of these indicating devices which the operator may 16 beusingatthctimatheswitchmemberfllis released thereby demergixing relay: 8' and 81 and the equipment then automatically follows the remote target.

The control electrodes of devices l0, l1, O8 and II are each connected through the respective transformer secondary, to a point between the resistances oi the respective pairs of cathode rosistances 2". III, III and Ill. If this connection were made to ground. then the cathode potential would follow the control electrode potential and no amplification by the respective discharge device would be had. By connecting the control electrodes to intermediate points upon the respective cathode resistances the amplification of the discharge devices IO, 81, II and ll is increased and, in addition, the cathodes may be at an average potential of the order of that between conductors 84 and conductors II. In this way operation of relays It and I! does not produce large abrupt changes in voltages between the control electrodes of devices 41. 4. and Il, ll.

In proximity to handle 83 is positioned a signal lam 2". Thislampisenergisedfromsource II. when either of two limit relays I41 and Ill becomes energized. These latter relays become energized in response to closure of limit switches 20! or 201, respectively. These switches are closed by operation or their respective armatures to either of two opposite positions from an intermediate position when corresponding shaft I or It is rotated to the limit of its movement.

Thus. for example, let us assume that the equipment is following a remote craft and that craft exceeds the range of the equipment in elevation. One of two pronls 2|. on shaft I engases the armature of switch 2 causing it to close its contacts and energiae relay I41. Relay 1 operates and opens the anode-cathode circuit of discharge devices 41 and ll thereby stopping the uuward movement of axis I and closing the circuit of lamp 2 IO. The operator. on observing the lamp and noting what has happened, may change the position of his own craft and reorient his equipment by use of handle I8 and thus again direct the equipment at the remote craft.

While we have shown a particular embodiment of our invention. it will of course be understood that we do not wish to be limited thereto since many modifications both in the circuit arrangement and in the instrumcntalities employed may be made, and we contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope or our invention.

Whatweclaimasnewand desiretosecureby Letters Patent of the United States is:

1. In combination, a directive radio receiving system, means to vary the orientation or said system about an area of remote space in a plane at right angles to the directive axis of said system in accord with a predetermined pattern, means responsive to waves received in said receiving system to maintain said system oriented in the direction of propagation of received waves, and means to control said orientation in joint response to action of both oi said two means.

2. In combination, a directive radio receiving system, means to vary the orientation of said system in accord with a predetermined pattern aboutanareaofremotespaceinaplaneat right angles to the direction of orientation of said system. means responsive to waves received insaidrcceivingsystcmtomaintainlaldmtem oriented in the direction of propagation of received waves, means responsive toradio waves received. during variation of said orientation in accord with said pattern to affect said orientation. means to indicate continuously said orientation, and means responsive to said received waves to interrupt operation of said first means.

3. The combination, in a directive radio receiving system, of a motor connected to vary the orientation oi said system, means cyclically to vary the voltage supplied to said motor to vary the orientation or said system in accord with a predetermined cycle, means responsive to waves received in said receiving system to control the voltage supplied to said motor, manual means operable in accord with desired directions of orientation of said receiving system, and means to control the voltage supplied to said motor to vary the orientation or said receiving system in responseto and-in accord with the operation of said manual means.

4. In combination, a directive radio receiving system, means to vary the orientation of said receiving system in accord with a predetermined pattern about a desired area of a remote plane at right angles to the directive axis or said system, a cathode ray device having a. viewing screen, means to indicate continuously on said viewing screen the Position of said orientation in said area, and means responsive to waves received in said receiving system during said variation in said orientation to alter said variation in orientation in said area whereby the reception of said waves is indicated on said screen.

5. In combination, a directive radio receiving system, means to vary the orientation of said receiving system in accord with a predetermined pattern about a desired area of a remote plane at right angles to the directive axis of said system, a cathode ray device having a viewing screen, means to indicate continuously on said viewing screen the position of said orientation in said area, means responsive to waves received in said receiving system during said variation in said orientation to vary said orientation in said area in accord with the direction from which said waves are received whereby the reception of said waves is indicated on said screen, and means to disable said first orientation varyin means whereby said variation is controlled by said received wave responsive means.

6. In combination, a directive radio system,

and means automatically to vary the orientation thereof about a rectangle in remote space, said means comprising a plurality of relays, means to operate each relay in response to variation in orientation oi said system from a predetermined direction to "a respective corner of said rectangle, and means responsive to operation of each relay to vary said orientation from said respective corner toward the next adjacent corner of said rectangle.

7. In combination, a directive radio system, voltage responsive means to vary the orientation of said system in either direction in a predetermined plane in accord with the polarity of voltage supplied thereto, means to supply two unidirectional voltages thereto, means to reverse the polarity of one of said voltages when said orientation is at either limit of its movement in said plane thereby to produce scanning action of said system in said plane, and means to control the polarity of said other volta e in accord with the relation between the direction of orientation of system and the direction of prop gation of motor means to maintain said system directed in the direction from which said signals arrive, electron discharge means responsive to said voltage to control said voltage supply means to prevent hunting of said system, and means responsive to predetermined variations in the orientation oi said system to control said electron discharge means to vary said orientation through a prede termined cycle.

9. The combination, in-a directive radio system, of motor means to vary the orientation thereof, a generator to supply voltage to said motor means, said generator having a pair of field windings, a pair of electron discharge devices each connected to control one of said field windings, means to control said discharge devices in response to signals received in said system to maintain said system directed in the direction from which said signals arrive, and means responsive to predetermined variations in orientation of said system to control said discharge device to vary said orienta= tion in accord with a predetermined cycle, the

control of said discharge devices by said first control means predominating over said control by said last control means whereby said predator mined cycle is interrupted in response to signals received in said system.

1c. The combination, in a directive radio system, of motor means to vary the orientation there of, a generator to supply voltage to said motor means, said generator having a pair of held it t ings, a pair of electron discharge devices each connected to control one of said field d t. and each having a pair of control grids, means responsive to predetermined variations in orientation of said system to supply voltages to one oi said control grids of each device to vary the orientation of said system in accord with a predetermined cycle, and means responsive to m: waves received in said system to supply potentials to the other control grid of. each of said devices to interrupt said cycle and to orient said system in'the direction from which said waves arrive.

11. The combination, in a directive radio system, of motor means to vary the orientation thereof, a generator to supply said motor, said generator having a pair of field windings, mea responsive to radio waves received in said system to vary oppositely the energization of said field windings thereby to vary said orientation in the direction from which said waves arrive, manual orienting means for said system, said manual means including a control member positionable in accord with the orientation desired, means re sponsive to said position of said control memher oppositely to vary the energization of said windings thereby to produce corresponding change in orientation of said system, and means responsive to change in position of said orientation to agree with the position of said control member to restore the energization of said windings.

12. The combination, in a radio scanning system, of motor means to vary the orientation of said system, electron discharge means arranged to have voltage applied thereto and to supply tem, voltage generating means to vary the orientation of said system to scan in accord with a predetermined pattern an area of remote space in 18 1,862,119

a plane perpendicular to the direction of orientation of vsaid system, means responsive to radio waves received by said system during operation of said first means to generate a second voltage in accord .with variation in the direction from which said waves are received, means selectively responsive to said two voltages in accord with their relative intensities for varying the orientation of said system, and indicating means responsive to said second voltage for indicating the I variation in orientation of said system.

RICHARD W. PORTER. ANTHONY G. LINOWIECKI.

Bar-masons crrnn The following references are oi record in the file of this patent:

UNITED STATES PATENTS Number Name Date Little June 7, 1932 1,915,328 Mirick June 27, 1933 2,138,966 Hai'ner Dec. 8, 1938 2,189,549 Hershberger Feb. 6, 1940 2,231,929 Lyman Feb. 18, 1941 2,308,521 Lear Jan. 19, 1943 2,409,448 Rost et al Oct. 15, 1946 

